1. Field of Invention
The present invention relates to the field of communications and, more specifically, to methods and systems for transmitting and receiving messages.
2. Description of Related Art
In today's world, information exchanges between people in many ways. In that regard, numerous types of communication systems exist for this purpose, including, for example, radio, television, cable, internet, two-way radio, cellular telephone systems, LANS, WANS, and optical communication systems. Advances in technology enable the distribution of information faster and more efficiently than was possible just several years ago. Some information is trivial, while other information can be critical and needs to travel immediately to the recipients.
In responding to emergency situations, the need for particular information relating to the emergency is sorely acute. Such emergency related information may include a threat of a disastrous event, terrorism induced threats and events, location and description of the event, evacuation instructions and status, and the status and coordination of the response to the threat or event. This information is invaluable to government and private agencies responsible for preventing, assessing, and responding to such events, and also by those on the front lines that are present at such an event and are dealing with it directly (e.g., “first responders” such as police, fire and rescue, emergency medical personnel). Fast and reliable dissemination of emergency information to emergency response personnel is necessary in order for the emergency to be contained and neutralized with minimal loss of life in terms of both emergency personnel and the general population.
Therefore, systems have been deployed to assist emergency personnel and responsible agencies in disseminating emergency alerting messages and notifications to emergency response personnel. However, such existing systems are notoriously slow and unreliable. Furthermore, many of these systems lack any practical confirmation mechanism from which the alert originator can ascertain whether or not a sufficient response team has been assembled or dispatched. For example, many agencies at all levels of government may employ a telephone based auto-dialer system in which emergency response personnel are contacted by telephone individually seriatim. Such systems may include, for example, a human dispatcher who simply begins contacting, one at a time, individual members of an emergency response team by dialing the emergency contact telephone number for each team member whose name appears on a predefined list corresponding to the type of threat or emergency. Alternatively, multiple operators may dial emergency personnel in parallel, or a computer-based auto-dialer may be used in which a voice message is played over the telephone to the answerer. Such systems and methods are plagued with limitations and inefficiencies, not the least of which is the slow speed at which a response team can be contacted and assembled, and provided with relevant information concerning the emergency. For example, telephone based auto-dialers typically contact emergency response personnel one-at-a-time, resulting in a slow notification process. Even in the case in which multiple dispatchers or auto-dialers are used, coordination problems may ensue in tracking which personnel have been reached and given positive confirmation of their response. For computer-assisted auto-dialers, the voice mail message played to an individual may not provide significant information specific to the emergency and, further, may not be customizable to include important information concerning the particular nature of the threat or event leading to the emergency situation.
Over and above all of these limitations, all voice-based existing systems and methods depend on the reliability and availability of the telephone service in providing emergency message notification. Unfortunately, both land line based and mobile telephone communication are vulnerable in times of emergency, in terms of both reliability and availability. Because telecommunication systems are designed to accommodate a statistical average number of voice users having a particular call duration (e.g., commonly modeled using the Erlang probability density function), voice circuits may become saturated or overloaded in an emergency situation in which many callers are attempting to connect using the voice carrying network. Wireless voice-based communications systems such as cellular telephone systems and their digital counterparts are also susceptible to overloading due to bandwidth limitations of and shared access to the radio channel. These situations occurred in certain metropolitan areas during the events of Sep. 11, 2001.
First responders may also use one or more radio-based systems for coordination and status of response activities, typically at the site of the emergency. Such radio systems may be simplex systems (i.e., one-way voice traffic only) and have a limited number of frequency channels for communications. In addition, different agencies and teams typically use different frequency channels, radios, and/or air interface technologies and modulation techniques (e.g, Single Side Band (SSB), Very High Frequency (VHF), spread spectrum). Thus, coordination among multiple government agencies responding to a large scale event is problematic, if possible at all. The current situation engenders at least confusion and inefficiency for those responding to emergencies and, of most concern, the potential for additional loss of human life.
Thus, there is a need for reliable and fast communication systems and methods that overcome these limitations of voice-based communications for disseminating alerts and notifications that may be, for example, associated with emergency prevention and response.